You can check the flapper motor. Start the car and look down inside the plastic windshield screen with the hood open. The flap will be in the open position then go in the car and turn on the recirculation button it should now be in the closed position. The internal vent positions are easy to test by changing the settings and seeing where air comes out. I'm sure you know this already.

I'm not sure if the B air conditioning system is the greatest. Mine adequately cools, I wouldn't say it sets any cooling records. My other cars seem to cool quicker.

 

I had AC issues, ended up replacing the compressor. I got a new one from Denso instead of Bentley as much cheaper for the same part. Also changed the restrictor, drier and AC rad. It's as cold as you like now.
With VCDS you can check the function and see the various pressures etc.
Original post below.

Replaced the compressor on my 2004 GT with one from Denso (I believe Denso manufacture the original compressor) the part number is DCP32052 it's much cheaper than the same part from Bentley. Also replaced the drier, condenser and restrictor valve.

 

I opened up the cowl and saw the flaps twitching open and close repeatedly. And I now know what's that electronic motor noise I randomly hear from the inside the car now. will keep all posted. Hopefully it's just as simple as this.
I've also done compressor, drier, and restrictor valve. I'm hoping the condenser doesn't need to be done.

 

The only time I've ever replace a condenser is it leaks. Although they do get plugged up if the compressor puked it's guts. This is why a pressure test on the high and low side is necessary. The restriction will show a high high pressure in relationship to the low pressure side.

 

Just as a for what it's worth: A couple weeks ago I posted on a flying spur thread my 2007 GT's AC seems totally dead... compressor not kicking on. So just this morning an AC buddy of mine and I checked the system pressure and that seemed fine. So we checked for codes with his Snap-on system... I had my VAG system with me, but we used his Snap-on system. Anyhoo: He asked if my check engine light is on? "No ('cause it isn't/wasn't). He said there's a code showing "no cooling fan signal". I explained the radiator cooling fans seemingly work. He cleared the code... we started the car, and "viola", the AC compressor kicked on, and the AC functions seemingly as normal... blowing nice cold air. The radiator cooling fans kicked on. I cycled the "ECON" feature of the AC control per the infortainment system and that kicked the compressor off... and kicked back on when I took it off ECON. Everything seems to be functioning fine, now.

 

Wow what a fantastic result ...

 

Update: The car wasn't keeping the cabin cool enough on the really hot days. Even when set all the down to "Low" and manual recirculation ON. Pressure readings were apparently normal. The replacement of the fresh air/recirc flap motors did nothing - additionally they are still twitching between open/closed positions! They reassured me the system had been previously cleansed out, but when they checked the restrictor valve again - it was completely black despite only having been replaced a couple months ago (and it's only been driven maybe 5 or 6 times since then). They recommend condenser placement now - seems like the only final thing to do? Or else I'll be going through restrictor valves every month.

 

In general an after-market inline filter is necessary once a compressor fails. Would recommend quarrying if it is possible on a Bentley. One of the ensuing problem of a failed compressor is the continuous debris in the system. I would be concerned about the receiver drier being contaminated. We realize it was just changed. With a heavily contaminated system everything had to be replaced. The proper procedure is a complete flush which isn't possible at all AC Service facilities.

 

What is the proper way to flush? I asked again and Seems they didn’t use nitrogen as you recommended. Just normal air. Given the level of contamination (blacked valve in such short time) any suggestions what should be replaced again? Thank you. I take it I should hold off on the condenser replacement?

just out of curiosity how come a failed compressor causes the debris?

 

This is an example of a type of a professional flushing product. An experienced HVAC automotive shop would have an integrated flushing system beyond what I posted.

The compressor has to be disconnected during this process because it does not allow passage through the other components. Normally it is not necessary to flush a new compressor. However your compressor is contaminated due to the debris circulating through the system. Therefore the compressor should be flushed which is another process.

The best thing to do is call around and find a dedicated Automotive AC service shop. What this means is they go beyond just basic freon service. Many independent automotive shops are not qualified in total HVAC service. A dedicated automotive air conditioning flushing system is very expensive. The independent shops are able to change the components as you found out but they sometimes miss a few steps. Some of the topshop's will subcontract the flushing and filling of the system out.

At this point if everything isn't checked the problem will continue. Whoever performs this service mention that the receiver / drier (even though it's new) could be compromised.

I feel for you. This is not a pleasant problem.

 

Yes wait until someone properly flushes the system.

The compressor failure that contaminates the system is when the piston and the cylinder walls mesh. Small pieces of aluminum and debris start to circulate in the system. Certainly there are other reasons but that's the main one.

Discuss with your HVAC person if they can install an inline filter. The inline filter is an insurance policy.

Short of a proper flushing and a new receiver drier(?) there is risk of improper function. Unfortunately this is not a Magic Bullet project.

 

Thanks so much! Looks like my garage has never even heard of this fluid let alone obtaining an aftermarket filter.

I am really frustrated and a bit helpless now - I've been asking around and I suspect only the dealer knows how to do it. I'm reluctant to go to them because Hong Kong dealers are ridiculously more expensive than North America (they quote US$4,000 for a regular oil change). Which is why I've started to go to an independent specialist who fixes a lot of Bentleys. Sadly I find Hong Kong's industry lacking in a lot of skill-set for things we take for granted in North America (e.g. It took me months to find a shop that could refinish a brush aluminum lip, and literally only one or two shops that know how to do "Dent Doctor" repair).

 

hi there , newbie to the forum but when you replaced ac compressor on your CGT was the engine removed or accessed it from underneath ?

 

No engine removal. They access from the front - bumper, radiator, those come out.

 

thank you for reply , just read different things and done say engine has to be dropped and others say what you just replied 👍🏼